Those three words belong to the same "semantic field", meaning that they basically have a similar meaning, but every word is a little bit different. Odd is differing markedly from the usual, ordinary, or accepted. For example: "A very odd way to show gratitude" or "She's got a really odd sense of humour". Strange is not before known, heard, or seen, peculiar, unfamiliar, exciting wonder or awe. For example: "He gave me a strange look" or "The language was strange to me". Awkward is lacking social grace and assurance, causing embarassment. For example: "an awkward newcomer" or "an awkward moment". Hope this helps! :)